Frequency Modulation (FM) broadcasting is a technique for transmitting broadcast in a wireless emission manner and transmitting audio signals in an FM manner by using the change of frequencies of high-frequency oscillation over amplitudes of the audio signals.
The China Mobile Multimedia Broadcasting (CMMB) system is a first system developed independently by China for various mobile terminals such as mobile phones, laptop computers and the like. Integratedly aerial and terrestrial coverage and domestic roaming achieved by using S-band signals supports not only 25 television programs but also up to 30 broadcast programs.
Since FM signals received at a mobile phone side are an analog signal, and electrical signals are affected by various interferences both from environment and from within a communication system during their transmission along a route, it is hard to separate noises and signals from each other after their combination, thereby lowering the communication quality; and the longer the route is the more the noises accumulate. In the CMMB system, the received broadcast signals are digital signals, which have the following advantages: 1. the use of advanced digital compression/decompression method enables the provision of Hi-Fi broadcast programs compliant with DRA audio standards; 2. in a weak-field-strength region, its powerful error correction capability can be performed so that no noises are heard; 3. other data services can be conducted conveniently.
At present, most terminals only support reception of broadcast signals in an FM manner, though the FM manner has advantages such as wide signal coverage and convenient reception, it provides users with limited experiences of tone quality due to disadvantages of analog signals; from the viewpoints of the stability of received signals, its extendibility and the richness of program contents provided, broadcast signals of the CMMB are superior, but since broadcast signals of the CMMB are not fully popularized so far, signals can not be well received in certain urban areas or small-sized cities.
Therefore, optimal broadcasting experiences cannot be provided to users by above individual signals in existing techniques.